Electrobike calls it the world's fastest hair dryer, but its Pi electric bicycle isn't even in the same league. It has half the wattage of a Conair - just 750 watts, or about 1 horsepower.

That's the federally mandated limit for an electric bicycle like the Pi, which does triple duty: It's a traditional pedal pusher, a motor-driven bike and an art piece. You can ride it as long as your legs and lungs hold out. Or just nudge the throttle with your thumb, and let the 36-volt pack of nickel metal hydride batteries do the heavy breathing. Or you can park it in the living room between your Eames chairs and Albero sofa and admire its arching architecture.

One look at it, and you know: Pi occupies a rarefied space in the world of two wheels. It isn't just the heady Euclidean name, Ayn Randian design or ultra-green cradle-to-cradle engineering that makes it so unique. It's also where it's sold.

Pi isn't available at bicycle, scooter or motorcycle shops. Beginning this month, it's available exclusively through Design Within Reach, a nationwide 65-store chain (including Greenwich and Westport) that offers super-stylish furniture and accessories at supposedly affordable prices.

With its mid-century modern profile and $7,200 price tag, Pi fits the bill.

I had the chance to test a preproduction version of Electrobike's ridable sculpture on its home turf of San Francisco. In the morning I spent with the bike, I found it to be more aesthetic than athletic, but overall, it was an impressive machine.

At 58 pounds, it was light enough that I could lift it off the pavement with my bare hands. Although it's significantly heavier than a regular bicycle, that wasn't an issue unless I was turning fast and hard. The bike's batteries are stuffed into Pi's elegantly curved backbone, which means the bulk of their weight is centered but carried high - not so heavy or high that they made the bike flop, but enough that I was aware of their presence.

In a straight line, that was irrelevant, especially when Pi is powered by the motor. Pi operates in three modes - pedal only, motor only and motor assist, which combines the two. I found myself riding mostly in the motor-assist mode, because my legs are in no shape to spin up San Francisco's Sisyphean hills on their own.

The motor kicked in when I pressed the throttle with my left thumb. Twisting the right hand grip, I was able to adjust the continuously variable planetary transmission to handle different grades of hills or flat pavement.

Made by NuVinci, in Oklahoma, the transmission integrates the motor and pedals into a single driveline so the bike can easily pull itself up a hill, while the flywheel not only produces electric energy but regenerates it when braking, so the energy is released again when it's spinning.

Pi's maximum speed is 20 mph stock, but with a little after-market hot rodding (a larger chain ring and gears), the bike is capable of about 46 mph.

Making those upgrades can change Pi's vehicle classification, however. In Connecticut, ramping up Pi's ability to exceed 30 mph makes it no longer legally a bicycle.

On a single electric charge, which takes about 2½ hours plugged in to a standard outlet, Pi has a range of 25 miles. Add an extra-range battery to its underbelly for an additional $750, and you've bought yourself another 25 miles. That's in motor-only mode. Pedal, and you can go as far as your hamstrings let you.

Even though Pi has a motor, it is legally recognized as a bicycle. That means it can go just about anywhere a regular bike can go - bike lanes, even public transit - except maybe hiking, recreational trails and sidewalks. In Connecticut, the operator must have a motor vehicle license.

No registration is required for an electric bicycle; a bicycle helmet is required, though Electrobike suggests a state-approved motorcycle helmet may be more appropriate.

The helmet is one of four items included in Pi's steep price. Electrobike also kicks in a luggage rack, a pair of panniers and three saddles.

Electrobike claims that fewer than 200 pounds of carbon dioxide are created in the manufacture of its Pi - 60 percent from the mining, transport and smelting of its aluminum monocoque frame and 40 percent in the manufacture of its other components.

That footprint is so faint as to be ghostly when compared to that of a mid-size car, which creates thousands of pounds of carbon-dioxide emissions in its manufacture and, according to the EPA, an additional 20 pounds per gallon of gasoline burned while driving .

Riding Pi creates zero emissions, whether it's pedal-operated or motor driven. It's charging the bike that creates its main carbon footprint, to the tune of about 210 pounds per year for a rider who uses it 100 miles per week with motor power.

Electrobike is making 500 of its Pi models. All of them are painted the same Ferrari red. But Electrobike has three similarly shaped models available through its website. For more information on the pedal-free Pi-e , the three-wheeled Pi 3 and a gas-electric hybrid motorcycle called Pi X, visit www.electrobike.com

A stoichiometric air/fuel mixture is approximately 14.7 times the mass of air to fuel meaning that to burn 1 gallon of gas, you need 14.7 times 6.2 lbs = 91.14 lbs of air.

Even accounting for the fact that a stoichiometric ratio of 14.7 will not be used- 12.25 to 1 is probably more realistic- so now we need 77 lbs of air and 6.2 lbs of fuel for a total of 83.3 lbs. of combined fuel and air. Therefore, we are not dealing with 20 lbs. from 6.3, but 20 lbs. from 83.3 lbs.

When the fuel burns, the hydrogen from the gas combines with oxygen to make H2O and the and the carbon from the gas combines with the oxygen to make CO2.

A carbon atom has a weight of 12, and an oxygen atom has a weight of 16, giving every molecule of carbon dioxide a weight of 44, 12 from carbon and 32 (16x2) from oxygen.

To calculate the amount of carbon dioxide which can come from a single gallon of gas, the weight of the carbon in the gasoline is multiplied by the weight of the total molecule divided by the weight of carbon alone, 44/12 or 3.67. This is because each CO2 molecule contains 3.67 times more oxygen by mass than it does carbon.

Gasoline is approximately 87% carbon and 13% hydrogen by mass, therefore, the carbon in a gallon of gas weighs about 5.5 pounds (87% of 6.3 lbs.). So where does the other approximately 14.5 lbs. of weight come from? The oxygen in the air- remember, CO2 is one carbon atom and 2 oxygen atoms. Take the weight of the carbon- 5.5 lbs. and multiply by the amount ratio required to determine the weight of oxygen needed to make CO2, 3.67, and you get 20.185 lbs. of CO2 from burning 1 gallon of gasoline.

Anyhoo- interesting looking bike- but $7,200? All except one of the cars I've owned in my life cost less.